This invention relates to rocket motors and particularly to the use of rocket motor bleed gases for actuation of rocket control devices. It has been found that the main rocket motor chamber can supply gas for actuation of thrust vector control means and thrust modulation control devices, for example, without impairing motor performance. However, this concept of conditioning motor bleed gases is fairly new and there are only a few designs using this concept. Of these designs, only a very few use a decomposing chemical to cool the gases and none are known which use a coolant as an aid to the filtration of alumina.
It appears to have been the consensus in the trade that aluminum oxide in hot hot gases could be easily filtered without cooling. However, such ease of filtration has not been found to be the case. At elevated temperatures the aluminum or its compounds in the gases emanating from a rocket motor chamber are in liquid form and very difficult or impossible to remove by filtration. According to the present invention a filter-cooler is provided which considerably lowers the temperature of the hot gases before filtering so that alumina in the gases solidifies and is more easily and efficiently removed, and the gases are, therefore, converted into gases suitable to operate auxiliary power devices.
Known prior art devices have relied principally upon gravity separation of the solid particles or porous type line filters. The principal disadvantage of the gravity filter is that a large free volume is needed to accomplish filtration. The in-line porous filter must have a large projected area to avoid plugging by the filtrate. According to the present invention a plurality of baffles having vortex producing port geometries are placed in series in the path of the gases. The rotational direction of each baffle is reversed in relation to the preceding baffle and the net effect is that the high rotational velocity of the generated vortex is used to separate the particulate contaminates from the gas stream by momentum. The contaminates then are carried radially by centrifugal force to the perimeter of the filter where they collect.